


It All Began With The Slap On The Ass

by LeeAusten



Category: Supernatural
Genre: Dean Winchester - Freeform, Destiel - Freeform, Destiel supernatural - Freeform, M/M, Sam Winchester - Freeform, dean and cas - Freeform, dean cas - Freeform, dean cas supernatural, destiel spn
Language: English
Status: Completed
Published: 2020-06-05
Updated: 2020-06-05
Packaged: 2021-03-04 04:33:50
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,582
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24547687
Author URL: https://archiveofourown.org/users/LeeAusten/pseuds/LeeAusten
Summary: Sam writes a long text to Eileen explaining exactly how he discovered that his brother and Castiel are sleeping together.
Relationships: Castiel & Dean Winchester, Castiel/Dean Winchester
Comments: 19
Kudos: 94





	It All Began With The Slap On The Ass

**Author's Note:**

> This is a prompt I got from a very good friend of mine: Bonnie Romo. Thank you for this! I loved writing it!

Hey Eileen,

Hope you're well, all packed and ready to come back to your tall, handsome prince with the most fabulous hair and body.

So, get this, and the story might take a while to flesh out, but you’ll end up getting a good laugh afterwards and maybe become as contented as I am by the outcome.

These two idiots: Dean and Cass, managed to fool me so damn good and really and truly, now I’m so ashamed to tell you the whole story. But I’m going to tell it anyway.

Here goes.

All of this began two freaking weeks ago and look, if it’s as embarrassing as it is to admit it now, I’m going to say it anyway. When Cass walked out on Dean, it was the ultimate breakup scene. I was there, hiding in the shadows but I saw and heard it all and Eileen, I’ve got to tell you, the whole thing made me cry like a baby.

You were there during the aftermath. You saw how Dean suffered through a heartbreak as obvious as anyone else could pick up. Binging on food like the goddamn world had just suffered through a famine. Walking around like a zombie everyday in pjs. Sleeping long hours and locking himself in his room. And worst of all, and I’m not going to hold back on admitting this, Dean cried himself to sleep every damn night and I could hear it through the walls.

Don’t lose interest now. I promise the best is yet to come but I needed to give you a little more backstory before I jump right into it.

When Castiel came back and the two of them patched up things, I was like all happy and fangirling because finally I’d get to see my brother happy again.

Had me questioning a few things all of a sudden though. Like why when Dean loses Cass, every single time he falls deeper into this destructive mood like jumping in to sacrifice himself if the need arises. Added to that, he would stop doing the things he love and hate himself even more.

Now about a week ago, we left the bunker, Dean and myself, to follow a lead on Chuck. Bad karma got us pretty good though when a house haunting came up along the way in Minnesota. And here was your boy (me) thinking that man, it’s easy peasy. We’d go in, salt and burn and get it over with. But was I wrong. The thing escalated into a ghoul and like a shitload of vamps and before we knew it, we were stuck for a while there.

Then one afternoon, just like that, you know, Dean told me that he was going to book a room for himself. He blamed it on me snoring and not being able to get enough sleep. Bull.

I smelled the lie but I didn’t bother too much about it because getting him out of my hair (literally) is more than enough to make me appreciate my own peace.

Next thing you know, guess who the hell shows up? CASTIEL, THE ANGEL OF THE LORDTH.

There I am going through some books on how to defeat Chuck because I like to swallow all the info I can get, and he appears like right in front of me. Funny part is, and this is where it gets interesting, Cass’ trench coat was missing. So there I was wondering what was wrong with him and why his damn cheeks were flushed.

“Sam,” he says, in that gravelly voice that sounds creepy after almost eleven years, “where is Dean. I can’t track him and I’m worried.”

So I said, “well hello to you too. I’m doing fine. Thanks for asking by the way.”

And the dude stares at me like I’ve offended him in the most offensive way ever.

I mean, Eileen, reason with me here, you know I’m not a bad guy. I’ve got great hair, a fantastic face and a perfectly sculpted body. Sure, my mind might be messed up but I got a balance going. And I appreciate good manners as much as anyone else who gives a shit. So, for this guy who I’ve always thought of to be my best friend, show up and ask where Dean is, I had a right to act the way I did. I’m not being moody about it.

Next thing you know, Cass is gone. Poof. So your man gets up, walks to the door and yanks it open. I’ve got my bitch face on, fists clenched and ready to brace Cass with a few choice words when I notice something right off the bat. The Impala is just nosing its way into the parking lot and after Dean spots Cass, he begins grinning like a fool.

I get back into the room and close the door barely allowing a little space to stare at the two of them.

Cass is on the steps, fists clenched and fuming and Dean springs out, he’s got a crinkled paper bag and three shakes and he’s still grinning.

“Got us some food, but let me drop this off real quick for Sam.” He steps away from Cass and as he’s about to come my way, his arm is taken and he’s yanked back. “Yo, not so rough, come on. We talked about this,” Dean says all convincingly innocent and shit. “What’s up with you?”

“I couldn’t find you when I came back here,” Cass rages. “I was so worried, Dean.”

“Stop being mushy, Cass.”

I’m like so okay, all cool, nothing weird about it although it sounds totally freaky that Cass got upset about going to Dean’s room and not finding him there. When he obviously knows that Dean takes off at weird hours to hit clubs, bars, women (which he hasn’t done in a long time) and burger joints. He’s obviously upset because after all these years, because he tattooed our ribs, all angels, himself included can’t find us.

But _stop being mushy, Cass?_

Since when does Dean us the word _mushy_?

Dean, in front of my eyes, I swear to the moon, leans in so close to Cass, and he says something that causes Cass to blush so deep, I never thought it was possible for his face to turn that color. Then doing that playful giggle that is only given to chicks he flirts with, Dean literally claps Cass on his ass and heads my way where I’m hiding.

I get away from the door, run to the table and sit down just in time.

“Sammy, stop reading so much, it will make your brain hurt,” he drops the paper bag in front of me and grins from ear to ear.

“What’s up with you?” I’m frowning so hard in that moment.

“Nothing much,” Dean scratches the back of his neck and avoids my eyes. “Just had a really good night.”

“You doing one-night stands again? Thought it wasn’t your thing anymore.”

“It’s nothing like that.”

“I mean, she had to be worth something. You’re shining bright like a diamond. That says as much as. And why is Cass looking for you? How come he just shows up? Did you call him? Because I didn’t.”

Dean suddenly stares at me and the smile drops from his face. “Wait, he was here asking for me?”

“He was. Plenty angry too.” At that point, I’m enjoying unhinging my brother in whatever way possible because he’s looking at me like I’m about to sprout another head. “I thought we were managing the case just fine.”

“We are. I mean, sure we are. It’s practically settled with this one. Just that we need to stick around to see if anything else pops up but we’re good.”

“So, why is Cass here?” I fold my arms and stare. “You two having a sleepover?”

“Look, man it’s just nothing. I wanted to ask him something about…something and I prayed him into the room. No big deal. I left right after he didn’t show for a while and obviously when I was gone, he came through.”

_And you clapped him on the ass?_

Oh, how I was fuming, Eileen because I knew that he wasn’t telling me the whole story. I knew deep down inside that there were cracks in his story and for some odd reason, at that point, the truth wasn’t obvious enough to me. Come to think of it now, I can’t believe how naïve I was. The first sign should have been the slap on the ass. But this handsome hunk here let it go.

Until…

I’m about to sleep, like nine in the night in my room, and I start hearing voices through the wall. My brother’s voice, he’s laughing happily and Cass’ low rumble then more laughter from Dean. So, I’m like wait, the two of them are having a good time over there and they’ve left me alone in my room.

I got up and I went over.

Who the hell told me to do that?

From the time I knock on the door, there are hushed voices and something clatters onto the floor. Then fumbling and the door is unlocked. And there stands my brother flushed in the face, shirt buttoned halfway and his hair is sticking out in all directions.

Naïve Sam, hello, hi, comes to the conclusion that he probably had a run in with Cas, maybe they fought or something and the laughter was them making up.

Making up my ass!

On the ride back to the bunker, Dean starts to play these soppy love songs that he usually scolds me for listening to. Like The Carpenters and Air Supply, and Tina Turner and Celine Dion. He’s belting out the lyrics when I turn the music down and ask him what the hell is going on.

Dean looks me in the face and tells me that he’s feeling pretty good and that I shouldn’t kill his mood.

I ask him why. He tells me that it’s because we had a good hunt.

Well, fine. We had a good hunt and we’re back on the obvious; trying to find a way to beat Chuck. And here he is as happy as a lark and singing to Taylor Swift’s ‘Everything Has Changed’.

How does he even know the lyrics to that song, I have no idea. But I eventually realize that there is only one other person who loves Taylor and that same person gave Dean a mixtape a year ago that he never played in the car because he said the music is too crappy.

So, guess what I did? I stopped the damn music and I ejected the freaking CD and there it was as bold as ever.

_**My Favorite Songs** _

_**\- Cas** _

I said nothing afterwards but he noticed. I just pushed the CD into the deck and let it play and I sat back and started fitting the pieces together.

Cass and Dean fight and break up.

They go to Purgatory and come back talking and laughing with each other.

Everything Cass says, Dean joins in and rambles on about a whole bunch of crap that he laughs at but Cass doesn’t.

Cass goes into Dean’s bedroom a lot to _talk_ and he never goes into my room to talk.

I wake up and I find Cass making coffee for Dean, who is still in his pjs.

Cass cooks Dean breakfast, serves him first and then gets to me after (don’t have a problem with this because I’ve gotten pretty used to the favoritism)

Dean reads poetry to Cass and it’s annoying as hell because it’s like he’s trying to be funny but it comes across as him being a complete douche.

Cass shows up randomly

Dean slaps Cass on his ass

We get to the bunker and I find Cass’ trench coat in the trunk of the Impala.

After I ask him why the coat is there, he ignores me and starts talking about noticing something when he watched Tombstone again last night (when I stormed over to his room).

So, my point is, when I think about it now, I see a pattern. But when I was going through the motions, it surprises me that I didn’t and maybe I should have been the first to know because I’ve been rooting for it to happen from the beginning. But I didn’t pick it up. I kept feeling like I needed to give Dean the benefit of the doubt because he’s never proven to me that he accepts it.

We haul the bags in. I jump into the shower. And whilst I’m in there, Cass finds the time to make dinner and fix Dean a plate. I walk into the kitchen toweling my hair dry and our eyes make four. And I’m thinking, well if you’re here so fast, then you had to be called to discuss something.

Cass fixes me a plate of some pretty good rice and beans and stewed chicken because he can actually cook and he’s a boss at it. And I sit down, ready to hear what’s up.

My bruh Dean stops eating, gets up and he actually pulls the damn chair out for Cass, who smiles at him and sits down.

I’m thinking, okay, gentleman-ways ain’t cheap. Something’s going on here and I smell a rat. So, I don’t say anything about it because I’ve been asking and getting no answers.

I decide to observe.

Later, my bruh pulls a disappearing act on me. I’m looking for him to ask about his take on what Chuck said about so many alternate universes existing, and Dean is nowhere to be found in the bunker. I get so angry after calling and he doesn’t pick up, that I grab a beer and sit by the Map Table waiting on him to show.

Next thing I know is, he’s there coming down the steps with Cass following.

“Where you two been?” I asked the million-dollar question.

Dean grunts in reply and heads to the kitchen. Cass on the other hand takes a chair next to me and sits down, clearly tired. And the first thing I notice is that he’s back in his trench but it’s wrinkled and the collar is turned up.

“Dean needed to vent.”

“About what?” I ask, staring at my _best friend_. “Or I should ask, what’s new?”

Cass sighs and shakes his head then pinches his forehead. “Chuck, you, the world.”

“Me?” I frown. “What about me?”

“The visions, the bond you have with _him_. And everything else.”

I should have focused on the last part. But I didn’t and because the obvious was playing with me oh so well, I kept on dancing to its tune.

“Okay, so I was meaning to ask him really and truly about his take on these alternate universes. If Chuck’s really right and these other worlds are fading, then the same can happen for ours, can’t it?”

“Yes,” Cass sounded terribly tired. “The worst part about Chuck is that he can do what he wants. Naturally, if he finds that something displeases him, he gets rid of it. We’re all his toys to play with.”

“Yeah, but what happens if he destroys all the worlds he’s created? Does the earth disappear from the solar system? All these worlds have to exist in some shape or form on one planet so…”

“You’re right and you’re wrong. There are rips in time, many parallels to one universe so although he may destroy all of these universes, ultimately the planet may still exist. Think of it as a stage where he gets rid of all the actors only to replace them with new ones when the time comes.”

“So he would wipe the earth clean and start over again? What kind of sick joke is that, Cass?”

“Whether we wish to deny it or not, he has the capability of killing every single human and he would do it, no questions asked. What I’m afraid of is what he will do to Heaven next. With an abundance of souls entering Heaven after their demise, we would have to deal with overcrowding and my only other thought as Dean mentioned earlier is if he chooses to turn these souls into angels.”

 _As Dean mentioned earlier_. Whilst you two were alone and chatty and confiding with each other? Away from me and everyone else and heaven knows where? Okay, Cass. You want to play a game? Two can play.

“So, if he kills us all, obviously you’d miss Dean the most, wouldn’t you?” I braved, “I mean, since you two have a _profound bond_ and all.”

Cass legit looked at me like I caught him in the act of doing something horrible like hoarding peanut butter in his trench coat.

“Don’t get me wrong,” I couldn’t stop myself, holding up my hands, “I don’t mind at all that you’re so close to each other. I like the fact that Dean has someone apart from me that he can confide in. But how would that hit you?”

“I’d be devastated,” Cass’ voice cracked. His blue eyes grew softer and I wanted to cry. “I’d miss both of you. You’ve become my best friend, Sam.” _The best friend that you’re hiding things from, I feel._ “And when it comes to Dean, I don’t think that I’d ever be able to recover from that. I’ve thought about how I will live for many years after his demise but I’ve never really stopped to think that Chuck may end the world any second and then I’d be left with nothing but pain.”

“Heartbreak.”

“It’s more than that. It’s like losing half of me.”

Well at least he’s honest unlike my damn brother. But what did I expect? A confession?

After all these years I realized one thing and I realized it with as much sadness as possible. Cass developed feelings for Dean, like hardcore feelings like I mentioned to you before. And Eileen, I’ve really admired how Cass has loved Dean for all these years because it might not feel like a long time to him because of how many years he’s existed.

But it’s pretty long for me.

I’ve watched Cass crumble from Dean being disappointed in him. I’ve watched him cry when Dean said that he means nothing to him. And I’ve watched Cass die inside when Lisa came back into the picture.

So, without a doubt I know his side of the story but I don’t really know Dean’s side. And it irks me because he’s good at hiding things, but the dude slips up somehow. And so far, it’s like he’s been slipping up and it’s becoming too obvious and like I still can’t buy it.

“You ever told him you’d feel like that?”

Cass looked at me and sighed. “Sam, I don’t want to hide the truth from you but Dean said that—”

“Bottoms up!” my brother interrupts, bringing three beers in and spreading them around with a wide grin. “Cheers to us for not giving up even though the world is kicking us plenty.”

I raise my beer after Cass and wonder if I’ll ever solve this mystery.

But I do, Eileen. Be proud of me a little even though I was so slow to catch on.

Two days after, I’m taking out the trash at night and you wouldn’t believe what I stumble onto.

As I’m about to lift the dumpster to throw the bag into it, I hear that same giggle my brother does when he’s flirty and riding high on happiness with women. And hating myself for being so damn nosy, I follow the sound to the side of the bunker where the car is parked.

In the shadows, I distinctly identify two figures leaning onto the right side and on the door. Dean is pinning someone between him and the car and he’s kissing the person long and deep and not coming up for air at all. His hands are buried between their bodies glued together and the other person’s hands are wound around his neck.

Dean’s always been a good kisser, I guess. He hooks them and draws them in good. But _this._ Man, it goes on for a long time whilst I stand there hating that the shadows hide the person’s face and I’m getting a good front seat view.

I mean, he goes at it. Dean dives in and gives her his all, as best as he can with clothes still on. Grinding into the woman and doing the whole head tilt thing to taste her neck. The moans follow. And because the night is so peaceful, I hear all of it, I began to get uncomfortable because he’s not going to stop and there I am eavesdropping on my brother making out with someone.

It’s when I’m about to turn around and head back in when I hear a name. Just one name. But a name that blows my mind.

Dean, in a low, seductive tone, says _Cass_. And up to that point, I’ll admit this Eileen, I remembered he had a girlfriend whose name was Cassie and I thought that he must have stumbled onto another girl with the same name because he couldn’t be kissing…

When the moonlight hit Cass’ face suddenly and illuminated his features, I almost bawl out for murder. I lost my shit right there and then, gawking and clawing at my throat because I couldn’t breathe. I started melting and losing blood. And my arms grew shorter and my hair lost its gloss and volume. My handsomeness evaded me.

Nah, I’m just being dramatic. I stood there and stared.

My brother, kissing Cass, the angel of the Lordth, the one who gripped him tight on the ass and raised him from perdition, leaving an angel hickey on his arm; a mark he obviously missed so much after it was gone.

It was too much to bear for me so I stumbled back into the bunker and after some time had passed, I heard footsteps shuffling in the hallway and then Dean’s door opened and closed too fast.

They were screwing each other. I KNEW IT. All this time, they were getting their freak on inside the bunker and in motel rooms and I keep wondering how long it has been going on for. Like, suppose they were screwing ages ago.

Eileen, can you imagine it? I’m not asking you to imagine them screwing. No! I’m asking you to imagine how clever they could have been to hide it all this time.

Dean sneaking out at nights and coming back I don’t know when because I don’t keep track. All sorts of things wrong about his behavior and yet I never picked up on it.

The day after that, which was yesterday, I met Dean in the kitchen and I stood there, arms folded.

And I was like, “so you and Cass, huh?”

Dean looked at me and wanted to prolong the lie. “What about me and Cass?”

“Don’t give me that crap, Dean. I know!” I flung my arms up and stared. “I know that you’ve been together. I mean, it should have hit me a long time ago because I saw you clap him on his ass and then I heard the two of you laughing in the motel room but—”

“Wait, what?” Dean stared at me, completely shocked.

“I know all about it, Dean. The soppy love songs in the car. The disappearing acts. The two of you coming back in with your clothes creased and your hair all over the place. I’m not stupid.”

“You’re crazy, not stupid.” He returned to sipping his coffee like I was a fool.

“I was taking out the trash last night, Dean. And I saw the two of you kissing. So don’t try to pretend that it’s not happening. And don’t get me wrong,” I sat down and sent him a soft look, “I’m not going to judge at all. In case you’re wondering, I’ve been rooting for the two of you to end up together since he saved you. But you kept hiding it from me and I don’t know why you did.”

For a long time he sat there looking at me and I thought that he would start crying. The look on his face was so tragic, Eileen. Like he was holding his breath for so long and when I admitted that I wouldn’t judge him, Dean just wanted to start breathing again.

I think in that moment I loved him a lot more than ever before, because he was relying on me so much for acceptance. And I kind of hated him a little too because out of all the people in the world, Dean honestly thought that I would be judgy about the whole situation.

“Sammy,” he said softly, his eyes tearing up, “thanks.”

“For what?”

“For not making a big deal about it.”

I sighed and shook my head. “Dean, it’s love. And it’s Cass. There’s no one better suited for you. How long have you two been together though?”

“Honestly?” Dean shrugged and looked so softer than I had seen him since Cass walked out, “since Purgatory. The place got to me. I prayed and laid it all out to him. I didn’t exactly say those three words but he got it. And when we got back here, well there was some things to get past. But we pulled through and we’re…here.”

“Kissing and everything else, huh?” I smirked and watched him grow beet red. “Hope you’re using protection because we already have a Nephilim. We don’t need another one.”

“Shut up,” Dean legit smiled and blushed some more. “That can’t happen. Anyway, I’m so happy that you’re okay with it. He’s been pestering me to tell you since it all began and he wanted me to tell you instead of him. I just didn’t have the guts to.”

“I mean, with everything that’s been going on with us and Chuck, I get why you felt cornered. But you know you can talk to me about anything, man. Remember, I’ve got your back.”

“Yeah, but having feelings about a dude is a whole other level. Ever since you always boasted about being religious, I didn’t know what to expect. And the thing is, with Cass, he’s become like a brother to you. So I thought that if I fessed up, it would sound pretty weird. And gross.”

“Nah, if it makes sense, I’ve never thought the two of you were like brothers. The profound bond thing always got me thinking that Cass loved you far more. You two planning on getting married?”

“One step at a time, bitch.”

“Jerk!”

So, Eileen. Therein lies the story that has shamed me because when we meet again, which is next week, you will come into the bunker and as soon as our eyes meet, Dean will realize that I’ve told you everything. But don’t go easy on him. Harass him. Tease him about it because he deserves it. And as for Cass…

Well, Cass gets off the hook after loving my brother for so long and not having that love reciprocated.

I just wish that I’d known sooner that Dean felt the same way. Then I could have played a good game of matchmaking.

I love you,

Sam.

**Author's Note:**

> I challenge you to write Eileen's response in the comments! Go!


End file.
